1. Field of the Invention
The present invention relates to a scanning probe microscopy cantilever, and furthermore to a scanning probe microscope including such a cantilever as well as methods for manufacturing the cantilever and for scanning a sample by making use of the cantilever.
2. Description of the Related Art
Although in principle applicable to arbitrary scanning probe microscopy investigations, the invention and its background will be explained with respect to investigations of semiconductor surfaces by tip-enhanced Raman spectroscopy (TERS). TERS is a relatively new technique for investigating sample surfaces that is based on a combination of scanning probe microscopy (SPM) and Raman spectroscopy. A sharp tip such as used in SPM is brought into close distance to or actual contact with a sample surface to be investigated, thereby forming a cavity between the end of the tip and the sample. An excitation laser is then focused onto the end of the sharp tip, illuminating the cavity with light of a wavelength that is longer than the dimensions of the cavity. Localized surface plasmons are excited in the apex of the tip and/or in the cavity, leading to a magnification of electromagnetic fields within the cavity, and in consequence to an intensely magnified Raman scattering signal that can be detected to obtain information about properties of the sample in the confined region pointed at by the tip.
The ability to obtain highly localized information e.g. about the chemical composition or local stress of the sample at a given location makes TERS useful in semiconductor development and manufacturing. However, adjustment of the tip and the laser beam relative to each other require careful calibration before TERS measurements can be performed, which makes it time-consuming and expensive to routinely employ TERS e.g. in semiconductor development or even production. Furthermore, in particular the investigation of high-aspect-ratio structures common in semiconductor manufacturing is made difficult since the shape of the tip, its orientation, as well as the direction of the laser beam have to be coordinated in order to enable both the laser light and the tip to reach the bottom of such structures.